US 12,345,635 B2
Ultrafast chemical imaging by widefield photothermal sensing of infrared absorption
Ji-Xin Cheng, Newton, MA (US); Yeran Bai, Allston, MA (US); Delong Zhang, Brighton, MA (US); Ali Shakouri, West Lafayette, IN (US); and D. Kerry Maize, West Lafayette, IN (US)
Assigned to Purdue Research Foundation, West Lafayette (MA)
Filed by Purdue Research Foundation, West Lafayette, IN (US)
Filed on Nov. 16, 2023, as Appl. No. 18/511,574.
Application 18/511,574 is a continuation of application No. 17/600,438, granted, now 11,867,620, previously published as PCT/US2019/065466, filed on Dec. 10, 2019.
Claims priority of provisional application 62/777,421, filed on Dec. 10, 2018.
Prior Publication US 2024/0159667 A1, May 16, 2024
Int. Cl. G01N 21/3577 (2014.01)
CPC G01N 21/3577 (2013.01) [G01N 2201/06113 (2013.01)] 44 Claims
OG exemplary drawing
 
1. A system for widefield imaging of infrared absorption properties of a sample using a photothermal effect, the system comprising:
an infrared pump source configured to generate an infrared pump beam;
a probe source configured to generate a probe beam;
at least one pulse generator configured to initiate a series of synchronized pulses of the infrared pump beam and probe beam;
a sensor configured to construct:
a first frame comprising a spatially-resolved image of probe light collected from the sample with the infrared pump beam intersecting the probe beam at the sample; and
a second frame comprising a spatially-resolved image of probe light collected from the sample with a reduced intensity of the infrared pump beam intersecting the probe beam at the sample; and
a processor configured to generate a plurality of signals indicative of a level of infrared absorption at each of a corresponding plurality of spatially-resolved points on the sample.